Slash'EM (Super Lotsa Added Stuff Hack - Extended Magic) is a variant of the roguelike game NetHack that offers extra features, monsters, and items. Several of its novel features, such as the Monk class, "conducts" (voluntary challenges), and the Sokoban levels, have been reincorporated into NetHack.

The main dungeon in Slash'EM is much larger than in NetHack, introducing special levels such as the Sunless Sea, where a magic lamp lies, and the Guild of Disgruntled Adventurers, populated by "player monsters" (archaeologists, barbarians, and the like).

Compared to NetHack, Gehennom comprises fewer levels, though it contains a special level for each demon lord and prince, including those who only appear when summoned in NetHack. These alterations serve to reduce player tedium that results from trekking through repetitive maze levels.